What version of Go are you using (go version)?

Both https://golang.org/pkg/sync/ and https://tip.golang.org/pkg/sync/

What did you do?

I wasn't sure whether to write "a RWMutex" or "an RWMutex", so I Googled it.

https://www.google.com/search?q=golang+%22a+rwmutex%22
https://www.google.com/search?q=golang+%22an+rwmutex%22

What did you expect to see?

I expected to see a considerably larger number of search results for one or the other of the Google results; or, I expected to see consistent usage in the sync documentation.

What did you see instead?

I saw 268 results for "a RWMutex" and 212 results for "an RWMutex". Then I noticed the sync docs were in both search results. "A RWMutex" occurs twice in the official docs and "an RWMutex" occurs 3 times.

According to this English StackExchange post, "a" vs. "an" comes down to how the word is pronounced out loud. "Read-write mutex" is fewer syllables than "arr-double-you mutex", so I can see why it's natural to write "a RWMutex". Ultimately I would like to see one style or the other in the official docs so I don't have to think about which style to use.